Low-moisture content shell layer, its coating method, and applications

Abstract

This invention relates to the semiconductor technology field and discloses a low-moisture-content shell layer, a coating method thereof, and its applications. In this invention, a polysiloxane layer is formed on the surface of a filler powder using T-unit siloxane as a raw material, then the polysiloxane layer is subjected to a drying treatment to reduce its moisture content, promote the condensation of silylhydroxy groups, arrange the organic groups of the T-unit siloxane in an orderly manner, and form a uniform polysiloxane layer. Finally, some of the organic groups of the T-unit siloxane are removed by a calcination treatment and converted to Q-units, converting the uniform polysiloxane layer into a dense siloxane compound shell layer. In this invention, by suitably selecting raw materials and optimizing the manufacturing process, the siloxane compound in the shell layer is made denser and more continuous, and the resulting shell layer has a low moisture content even after being left for a long time, and thus the filler powder having the shell layer has the advantage of having a low moisture content.

Description

[Technical Field]

[0001] This invention relates to the semiconductor technology field, and more particularly to a low-moisture-content shell layer, a method for coating the same, and its applications. [Background technology]

[0002] With the rapid development of microelectronics and communication technologies, semiconductor chips are constantly evolving towards higher integration, miniaturization, higher frequency, and higher power, leading to increasingly demanding performance requirements for electronic core devices. In the semiconductor field, circuit board materials such as high-density wiring boards, high-frequency / high-speed boards, and motherboards are needed when integrating passive components, semiconductor components, electroacoustic devices, display devices, optical devices, and radio frequency devices into equipment.

[0003] Substrate and packaging materials for electronic devices need to have low moisture content to minimize dielectric loss during operation and reduce the risk of the device turning on due to the presence of moisture. Therefore, to meet the filler requirements of the semiconductor field, it is necessary to reduce the water absorption and moisture content of fillers in the substrate and packaging materials of electronic devices.

[0004] Existing semiconductor fillers are mainly classified into two categories: thermally conductive materials and flame-retardant materials. The former primarily functions as a thermal conductor, improving the heat dissipation effect of heat-generating components within electronic devices, while the latter primarily functions as a flame retardant to prevent direct combustion after heating of electronic devices. To enhance the filling effect of the filler, it is necessary to mix the filler with a resin material before loading. Typically, the surface of the filler is modified to improve the mixing effect between the filler and the resin material.

[0005] For example, to improve the bonding performance between diamond thermal conductive materials and other materials, Chinese patent application publication number CN114477167A discloses a modified diamond composite functional material and a method for manufacturing the same. This patent proposes coating the surface of diamond fine powder with a nanoamorphous SiO2 film that enhances the surface reaction activity of the diamond fine powder, thereby forming a good crosslinking reaction with the -OH groups in the resin by the reactive oxygen groups in the film, and improving the adhesion effect between the diamond and the resin binder. However, the surface of the diamond fine powder in this patent is rough, and there are relatively many gaps in the formed SiO2 film. In this patent, since the diamond fine powder with surface reaction activity obtained using the SiO2 film is applied to diamond abrasives, it is only necessary to graft reactive oxygen groups onto the surface of the modified diamond fine powder, and there is no need to consider the porosity and water absorption issues of the diamond fine powder. However, in the semiconductor field, an increase in the porosity of a filler means an increase in its specific surface area. The functional relationship between the specific surface area and particle size is specific surface area = constant / particle size. From this inverse relationship, it can be seen that as particle size decreases, the specific surface area increases sharply. On the other hand, an increase in specific surface area leads to an increase in the amount of adsorbed water, which in turn increases the dielectric loss of the semiconductor device, ultimately affecting the performance of the semiconductor device.

[0006] Therefore, in the semiconductor field, modifying filler powders requires not only improving the adhesion between the filler powder and the resin, but also reducing the moisture content of the modified filler powder. [Overview of the project]

[0007] Conventional surface modification of semiconductor fillers results in a higher moisture content in the modified product. To solve the above technical problem, the present invention provides a low-moisture-content shell layer, a coating method therefor, and its applications.

[0008] First, the present invention relates to solid 29By providing a low-moisture-content shell layer in which the ratio of the peak integral area in the -80 ppm to -120 ppm range and the +20 ppm to -120 ppm range in the Si-NMR nuclear magnetic resonance spectrum is 50 to 99.5:100, it can be applied to the semiconductor filler field and will have a relatively low water absorption even after being left for a long time, and will have excellent dielectric properties.

[0009] Next, the present invention provides a method for coating a shell layer with a low moisture content. By suitably selecting raw materials and optimizing the manufacturing process, the siloxane compound in the shell layer is made denser, and the moisture content remains low even after being left for a long time.

[0010] Furthermore, the present invention provides a filler powder containing a low-moisture-content shell layer, and further improves the affinity between the powder and the resin material, resulting in relatively low dielectric loss during the operation of an electronic device.

[0011] Furthermore, the present invention provides an application of filler powder containing a water-containing shell layer in the manufacture of packaging materials or substrate materials in the semiconductor field.

[0012] The specific technical solutions of the present invention are as follows. In a first embodiment, the present invention provides a shell layer with a low moisture content. The shell layer has the following characteristics. The aforementioned shell layer has a range of +20 ppm to -120 ppm. 29 It contains siloxane compounds that respond in Si-NMR nuclear magnetic resonance spectra.

[0013] solid 29 In the Si-NMR nuclear magnetic resonance spectrum, the ratio of the peak integral area of ​​the shell layer in the -80 ppm to -120 ppm range and the +20 ppm to -120 ppm range is 50 to 99.5:100.

[0014] In the semiconductor field, in order to improve the filling effect of fillers, it is necessary to mix the filler with a resin material before loading. Furthermore, in order to better mix the filler and the resin material, it is necessary to improve the affinity between the filler and the resin by surface modification of the filler.

[0015] Therefore, based on the above problem, the present invention relates to a range of +20 ppm to -120 ppm 29 The present invention provides a siloxane compound shell layer that responds in Si-NMR nuclear magnetic resonance spectra. By placing this shell layer on the surface of a filler powder, the activity of tight adhesion between the filler and other substances can be improved, resulting in better adhesion between the filler and resin material and an improved mixing effect.

[0016] The shell layer of the present invention is solid 29 In Si-NMR nuclear magnetic resonance spectra, the ratio of the peak integrated areas in the -80 ppm to -120 ppm range and the +20 ppm to -120 ppm range is 50 to 99.5:100.

[0017] In the semiconductor field, in the actual application process of fillers, they are generally not used immediately after manufacturing and have a storage period during which they absorb moisture. The shell layer provided by the present invention is placed on the surface of the filler powder, so the amount of water absorbed by the filler powder after storage is reduced, and the problem of dielectric loss due to high moisture content can be avoided.

[0018] In the siloxane compound shell layer provided by the present invention, the amount of a specific siloxane compound must be kept within a certain range in order to uniformly coat the surface of the filler powder with the siloxane compound shell layer. If the amount of the siloxane compound is too small, the siloxane compound cannot completely coat the surface of the filler powder, resulting in a shell layer that is not continuous, has high porosity, and suffers from water absorption problems later on. If the moisture content of the filler powder is too high, the risk of electronic devices turning on increases, affecting the operation of the electronic devices, and simultaneously causing relatively large dielectric losses. If the amount of the siloxane compound is too high, aggregation occurs in the filler powder, making it difficult to uniformly mix with the resin, causing delamination in the mixed filler formed by the coated filler and resin, increasing the formation of pores in the mixed filler of the filler powder and resin, and leading to water absorption problems. Therefore, the present invention relates to solid 29 This provides a shell layer in which the ratio of the peak integral areas in the -80 ppm to -120 ppm range and the +20 ppm to -120 ppm range in the Si-NMR nuclear magnetic resonance spectrum is 50 to 99.5:100.

[0019] In the siloxane compound shell layer provided by the present invention, the selection of the core material may affect the moisture content of the product containing the shell layer after standing. When the core material is a filler material with high surface energy, such as boron nitride, diamond, or aluminum nitride, the moisture content of the product after standing is generally higher than that of core materials with relatively low surface energy, such as organophosphorus flame retardant powder, metal magnetic powder, or alumina powder. This is because core materials with high surface energy may form fine gaps between themselves and the shell layer after coating, resulting in relatively high porosity and further water absorption problems. Ultimately, the moisture content of core materials with high surface energy is generally lower than that of core materials with low surface energy.

[0020] As a preferred shell layer of the present invention, the siloxane compound is obtained by production using siloxane containing 90%wt or more of T units as a raw material, wherein T unit = R₁SiO₃⁻, and R₁ is a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms that can be independently selected.

[0021] The siloxane compound shell layer provided by the present invention has relatively high compactness and relatively good continuity. A siloxane compound film obtained by production using polysiloxane containing 90%wt or more of T units as a raw material has relatively high compactness and relatively good continuity. For coating filler powder, it is necessary to condense the silyl hydroxy groups of siloxane to form a polysiloxane film layer on the surface of the filler powder, and further obtain the siloxane compound through heat treatment. In the process of forming the polysiloxane film layer, T-unit molecules are easier to rotate freely than Q-unit molecules, which is conducive to forming a uniform, continuous and dense film layer. The shell layer provided by the present invention has the advantage of low water absorption after being left standing, so it needs to be obtained by production using polysiloxane containing 90%wt or more of T units as a raw material.

[0022] More preferably, the T-unit siloxane is selected from hydrocarbon-based trialkoxysilanes and hydrocarbon-based trichlorosilanes.

[0023] As a preferred shell layer of the present invention, the thickness of the shell layer is 0.5 nm to 300 nm.

[0024] As a preferred shell layer of the present invention, after being left standing for 48 hours under environmental conditions of 25°C and 50%RH, the Karl Fischer moisture content of the product comprising the shell layer measured at 200°C is 160ppm / m 2 or less.

[0025] The siloxane compound shell layer provided by the present invention has relatively good compactness and continuity. Therefore, due to the excellent characteristic of low water absorption after standing of the filler powder provided with the shell layer, the water absorption of the filler powder during storage can be reduced, so that an electronic device can have a relatively low turn-on risk during operation and relatively low dielectric loss.

[0026] In a second aspect, the present invention provides a method for coating a low moisture content shell layer, comprising: Step S1: adding T-unit siloxane to filler powder to be coated with a shell layer and allowing a reaction to form polysiloxane on the surface of the powder to be coated with the shell layer, thereby obtaining a precursor; Step S2: performing a drying treatment to bring the precursor to a low moisture content state; and Step S3: performing a firing treatment to densify the surface of the precursor and obtain a shell layer on the surface of the filler powder, wherein the T unit is R1SiO3-, and R1 is a hydrogen atom or a hydrocarbon group having 1 to 16 carbon atoms that can be independently selected.

[0027] In the prior art, in order to improve the adhesion between filler powder and a resin material, attention is usually focused on the affinity of the surface of the filler powder. However, while improving the surface affinity of the filler powder, reducing the moisture content of the product should receive more attention in the art. The reason is that the presence of moisture in the filler not only causes the problem of dielectric loss, but also leads to the risk of turn-on failure of electronic devices.

[0028] To improve the density of the siloxane compound shell layer of a filler powder and reduce the amount of water absorbed by the product after standing, the present invention provides a method for producing the above-mentioned shell layer, which forms a uniform, dense siloxane compound film layer on the surface of the filler powder. First, the present invention uses T-unit siloxane as a raw material to form a polysiloxane layer on the surface of the filler powder. Next, a drying treatment is performed to bring the polysiloxane layer to a state with a low moisture content, promoting the condensation of silyl hydroxyl groups and arranging the organic groups of T-unit siloxane in an orderly manner, thereby forming a uniform polysiloxane layer and easily forming a dense siloxane compound. Finally, a calcination treatment is performed to remove some of the organic groups of T-unit siloxane, converting the uniform polysiloxane layer into a dense siloxane compound shell layer.

[0029] The conditions for forming a dense siloxane compound shell layer on the surface of the filler powder of the present invention include the following three points. (1) Because T-unit siloxanes are polar, when mixed with filler powders, they can be rapidly adsorbed onto the surface of the filler powders and form a polysiloxane film layer. Therefore, the first condition of the manufacturing method of the present invention is that T-unit siloxanes are used as raw materials. Since T-unit molecules rotate freely, the first condition of using T-unit siloxanes as raw materials is a prerequisite for step S2 of the present invention, which promotes the rotation of the organic groups of the siloxane by making the polysiloxane film layer have a low moisture content, thereby optimizing its arrangement.

[0030] (2) The second condition of the manufacturing method of the present invention is to dry the polysiloxane film layer to a state with a low moisture content, thereby promoting the rotation of the organic groups of the T-unit siloxane, arranging them in an orderly manner, and forming a uniform polysiloxane layer. A uniform polysiloxane layer is useful for forming a uniform, dense siloxane compound shell layer. (3) The third condition is to remove some of the organic groups of the polysiloxane shell layer by calcination, densify it, and convert the uniform polysiloxane layer into a uniform and dense siloxane compound shell layer under the said conditions.

[0031] In the preferred coating method of the present invention, in step S1, the mass ratio of the filler powder to the added T-unit siloxane is 100:0.2 to 10.

[0032] In a preferred coating method of the present invention, a basic aqueous solution is added in step S1 and the reaction is carried out.

[0033] Step S1 is a reaction in which T-unit siloxane is adsorbed onto the surface of the filler powder to form a polysiloxane film layer. Adding a basic aqueous solution can accelerate the reaction and promote the condensation of silyl hydroxyl groups. The basic aqueous solution may be one or more of the basic aqueous solutions of aqueous ammonia, tetramethylammonium hydroxide, choline, ethylenediamine, isopropylamine, and ethanolamine.

[0034] A preferred coating method of the present invention involves further adding silica powder and allowing the reaction to proceed.

[0035] More preferably, the particle size of the silica powder is 10 to 100 nm.

[0036] To further improve the density of the siloxane compound shell layer, the present invention also adds nanosilica powder when forming the polysiloxane shell layer in step S1. The siloxane compound coated on the surface of the filler powder in the present invention may be mostly obtained from T-unit siloxane raw materials, and a small amount may be nanosilica powder added directly. When siloxanes condense to produce polysiloxane, the reaction process is not dense, and a small amount of silica powder is added and dispersed in the polysiloxane skeleton. When the polysiloxane organic groups are removed by calcination in step S3, these silica powders fill the positions of the organic groups, reducing defects in the coating of the siloxane compound shell layer on the surface of the filler powder. Here, the particle size of the silica powder is preferably 10 to 100 nm, and the amount added is preferably 0.5% to 1.2% of the mass of the T-unit siloxane raw material.

[0037] In the preferred coating method of the present invention, in step S1, the particle size of the filler powder is 0.05 to 40 μm.

[0038] To form a uniform siloxane compound shell layer on the surface of the filler powder, the particle size of the filler powder must be within the range of 0.05 to 40 μm. If the particle size of the filler powder is too small, it is prone to aggregation, and the T-unit siloxane does not adhere uniformly to the surface of the filler powder. As a result, it is difficult to form a uniform polysiloxane film layer, and complete coating is not possible, leading to a low coating effect. Because the thickness of the siloxane compound requiring coating is relatively small and the amount of T-unit siloxane raw material added is relatively small, if the particle size of the filler powder is too large, the siloxane does not adhere uniformly to the surface of the filler powder, resulting in an uneven coating and a relatively high porosity. In this case, increasing the coating thickness and the amount of added siloxane raw material promotes a uniform coating, but this results in aggregation of the filler powder. Due to this aggregation, the filler powder after the shell layer coating is difficult to mix uniformly with the resin, and delamination occurs in the mixed filler formed by the product and resin. This also increases the formation of pores in the mixed filler of the filler powder and resin, leading to water absorption problems.

[0039] In a preferred coating method of the present invention, in step S2, the moisture content of the precursor is reduced to 0.1-1% by drying.

[0040] By reducing the moisture content of the polysiloxane layer, the rotation of the organic groups of the T-unit siloxane is promoted, causing them to be arranged in an orderly manner, forming a uniform polysiloxane layer. Furthermore, the resulting siloxane compound shell layer is made denser and more uniform, ultimately reducing the amount of water absorbed by the product after standing and lowering the moisture content of the product after standing. When the moisture content of the precursor is 0.1-1%, the density of the siloxane compound shell layer formed on the surface of the filler powder is highest.

[0041] More preferably, the drying method involves heating to 50-200°C and drying for 6-24 hours.

[0042] In a preferred coating method of the present invention, the firing treatment in step S3 is carried out in an inert gas atmosphere.

[0043] In the preferred coating method of the present invention, the firing temperature in step S3 is 600 to 1200°C.

[0044] The action of the calcination treatment is to remove the organic groups of the T-unit siloxane and convert the uniform polysiloxane layer into a dense siloxane compound layer. The calcination treatment is carried out in an inert gas atmosphere and has an excellent densification effect. The treatment temperature is preferably 600 to 1200°C and the duration is preferably 6 to 72 hours.

[0045] In the preferred coating method of the present invention, the firing treatment time in step S3 is 6 to 72 hours.

[0046] In a third embodiment, the present invention provides a filler powder comprising the low-moisture-content shell layer described above. The filler powder may be one or more selected from thermally conductive materials and organophosphorus flame retardants commonly used as fillers in the semiconductor field. For example, the filler powder may be one or more selected from boron nitride, PQ60, alumina, and aluminum nitride.

[0047] In a fourth aspect, the present invention provides an application of filler powder in the manufacture of semiconductor packaging materials or substrate materials. In the semiconductor field, when incorporating passive components, semiconductor components, electroacoustic devices, display devices, optical devices, radio frequency devices and the like into equipment, substrate materials for circuit boards such as high-density wiring boards, high-frequency / high-speed boards and motherboards are required. These substrate materials are generally mainly composed of organic polymers such as fillers and resins. The application provided by the present invention described above in the manufacture of semiconductor packaging materials or substrate materials can effectively meet the needs for high affinity of resin materials in semiconductor packaging materials or substrate materials, and can also meet the needs for low moisture content and low water absorption.

[0048] Compared with the prior art, the present invention has the following technical effects. (1) In the prior art, coating modification of filler powder generally does not consider the problems of water absorption and moisture content. However, in the semiconductor field, regardless of whether it is a filler or an electrically sensitive material, it is generally not used immediately after manufacture and has a storage period, so it is necessary to pay attention to the problem of water absorption during standing and the problem of moisture content after standing. The present invention provides a siloxane compound shell layer (the siloxane compound responds in the range of +20 ppm to -120 ppm in the 29 Si-NMR nuclear magnetic resonance spectrum) on the surface of 29 filler powder, and sets the ratio of the peak integrated area of the shell layer in the range of -80 ppm to -120 ppm and the range of +20 ppm to -120 ppm in the Si-NMR nuclear magnetic resonance spectrum to 50 to 99.5:100. Due to the excellent property of reducing water absorption of the shell layer after standing, arranging the shell layer on the surface of the filler powder can improve the activity of tightly bonding the filler and other substances, which not only enables better bonding between the filler and the resin material, but also reduces the water absorption of the filler powder during the storage period, further avoids the problem of dielectric loss caused by high moisture content, and reduces the risk that electronic devices operate at high frequencies and are turned on.

[0049] (2) The present invention further provides a method for coating a shell layer with a low moisture content. Using T-unit siloxane as a raw material, a polysiloxane layer is formed on the surface of a filler powder. Next, the polysiloxane layer is subjected to a drying treatment to reduce its moisture content, promote the condensation of silylhydroxy groups, arrange the organic groups of the T-unit siloxane in an orderly manner, and form a uniform polysiloxane layer. Finally, some of the organic groups of the T-unit siloxane are removed by a calcination treatment and converted to Q-units, converting the uniform polysiloxane layer into a dense siloxane compound shell layer. The present invention makes the siloxane compound of the shell layer denser and more continuous by suitably selecting the raw material and optimizing the manufacturing process, and the resulting shell layer has a low moisture content even after being left for a long time.

[0050] (3) In the siloxane compound shell layer provided by the present invention, the selection of the core material may affect the moisture content of the product containing the shell layer after standing. When the core material is a filler material with a high surface energy, such as boron nitride, diamond, or aluminum nitride, the moisture content of the product after standing is generally higher than that of core materials with relatively low surface energy, such as organophosphorus flame retardant powder, metal magnetic powder, or alumina powder. The siloxane compound shell layer provided by the present invention can further provide a filler material with a lower moisture content by suitably selecting the core material. [Modes for carrying out the invention]

[0051] The present invention will be further described below in accordance with the examples. Those skilled in the art will be able to realize the present invention based on these descriptions. Furthermore, the examples of the present invention described below are usually only a selection of examples, not all examples. Accordingly, based on the examples of the present invention, those skilled in the art should realize, without requiring any creative effort, that all other examples obtained should be included within the scope of the claims of the present invention.

[0052] The moisture content of the powder particles was measured at 200°C using a Karl Fischer moisture meter, specifically a Mitsubishi Chemical CA-310, and the measurement method was coulometric. In the performance test, the unit of moisture content was ppm / m³. 2 The moisture content was calculated by dividing the measured moisture content by the geometric external surface area of ​​the test particle (calculated using the measured average particle size).

[0053] The average particle size was measured using a Beckman Coulter LS-13320 laser particle size analyzer, with deionized water as the solvent. In this specification, the average particle size refers to the volume-average diameter of the particles.

[0054] Siloxane compounds 29 In the Si-NMR nuclear magnetic resonance spectrum, the total content of groups bonded to Si was expressed as the peak integral area in the range of +20 ppm to -120 ppm, and the content in Q units was expressed as the peak integral area in the range of -80 ppm to -120 ppm. The shell layer provided by the present invention had a ratio of 50 to 99.5:100 between the peak integral area in the range of -80 ppm to -120 ppm and the peak integral area in the range of +20 ppm to -120 ppm.

[0055] The coating thickness of the siloxane compound, i.e., the thickness of the shell layer, was measured using a high-resolution transmission electron microscope. [Examples]

[0056] Example 1 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0057] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0058] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 1.0 nm.

[0059] Example 2 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0060] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.1%.

[0061] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 1.0 nm.

[0062] Example 3 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0063] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 1%.

[0064] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 1.0 nm.

[0065] Example 4 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 0.5 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0066] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0067] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 12.9 nm.

[0068] Example 5 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 6.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0069] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.8%.

[0070] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature to obtain a dense siloxane compound shell layer continuous with the surface of the boron nitride powder particles. The thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 125.1 nm.

[0071] Example 6 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 0.05 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0072] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0073] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 0.5 nm.

[0074] Example 7 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 40 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0075] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0076] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. The thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 191.8 nm.

[0077] Example 8 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 40 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 42:1:1.

[0078] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0079] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. The thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 298.9 nm.

[0080] Example 9 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 12 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia and nanosilica powder were added and reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. The mass ratio of boron nitride powder, MTMS, 5% volume-concentrated aqueous ammonia and nanosilica powder was 50:4:4:0.01. The average particle size of the nanosilica powder was 30 nm.

[0081] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0082] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 6 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. The thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 121.1 nm.

[0083] Example 10 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 12 μm and mixed uniformly. Then, 5% ammonia water and nanosilica powder were added and reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. The mass ratio of boron nitride powder, MTMS, 5% ammonia water, and nanosilica powder was 50:4:4:0.01. The average particle size of the nanosilica powder was 10 nm.

[0084] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0085] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 6 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature to obtain a dense siloxane compound shell layer continuous with the surface of the boron nitride powder particles. The thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 119.3 nm.

[0086] Example 11 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 12 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia and nanosilica powder were added and reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, 5% volume-concentrated aqueous ammonia and nanosilica powder was 50:4:4:0.01. Here, the average particle size of the nanosilica powder was 100 nm.

[0087] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0088] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 6 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. The thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 134.4 nm.

[0089] Example 12 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 12 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia and nanosilica powder were added and reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. The mass ratio of boron nitride powder, MTMS, 5% volume-concentrated aqueous ammonia and nanosilica powder was 50:4:4:0.01. The average particle size of the nanosilica powder was 7 nm.

[0090] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0091] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 6 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 112.0 nm.

[0092] Example 13 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 12 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia and nanosilica powder were added and reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. The mass ratio of boron nitride powder, MTMS, 5% volume-concentrated aqueous ammonia and nanosilica powder was 50:4:4:0.01. The average particle size of the nanosilica powder was 120 nm.

[0093] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0094] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 6 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. The thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 134.5 nm.

[0095] Example 14 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 12 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia and nanosilica powder were added and reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. The mass ratio of boron nitride powder, MTMS, 5% volume-concentrated aqueous ammonia and nanosilica powder was 50:4:4:0.019. The average particle size of the nanosilica powder was 30 nm.

[0096] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 50°C, and dried at a constant temperature for 10 hours to reduce the moisture content of the precursors to 0.6%.

[0097] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 1000°C at a heating rate of 5°C / min and maintained for 10 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 126.4 nm.

[0098] Example 15 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to boron nitride powder with an average particle size of 12 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia and nanosilica powder were added and reacted at 25°C to form a polysiloxane on the surface of the boron nitride powder, obtaining a precursor. Here, the mass ratio of boron nitride powder, MTMS, 5% volume-concentrated aqueous ammonia and nanosilica powder was 100:8:8:0.01. Here, the average particle size of the nanosilica powder was 30 nm.

[0099] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 200°C, and dried at a constant temperature for 6 hours to reduce the moisture content of the precursors to 0.6%.

[0100] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 1200°C at a heating rate of 5°C / min and maintained for 24 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature, and a dense siloxane compound shell layer was obtained that was continuous with the surface of the boron nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 115.6 nm.

[0101] Example 16 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to diamond fine powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the diamond fine powder particles, obtaining a precursor. Here, the mass ratio of diamond fine powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0102] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0103] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 600°C at a heating rate of 5°C / min and maintained for 8 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature to obtain a dense siloxane compound shell layer continuous with the surface of the organophosphorus flame retardant powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 0.9 nm.

[0104] Example 17 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to aluminum nitride powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the aluminum nitride powder particles, thereby obtaining a precursor. Here, the mass ratio of aluminum nitride powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0105] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0106] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 900°C at a heating rate of 5°C / min and maintained for 6 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature to obtain a dense siloxane compound shell layer continuous with the surface of the aluminum nitride powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 1.5 nm.

[0107] Example 18 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to organophosphorus flame retardant powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% ammonia water was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the organophosphorus flame retardant powder particles, thereby obtaining a precursor. Here, the mass ratio of organophosphorus flame retardant powder, MTMS, and 5% ammonia water was 50:1:1.

[0108] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0109] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature to obtain a dense siloxane compound shell layer continuous with the surface of the organophosphorus flame retardant powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 1.2 nm.

[0110] Example 19 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to a metal magnetic powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the metal magnetic powder particles, thereby obtaining a precursor. Here, the mass ratio of metal magnetic powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0111] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0112] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a firing treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature to obtain a dense siloxane compound shell layer continuous with the surface of the metal magnetic powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 1.2 nm.

[0113] Example 20 A continuous, dense siloxane compound shell layer was provided and manufactured according to the following method. In step S1, methyltrimethoxysilane (MTMS) was added to alumina powder with an average particle size of 1.0 μm and mixed uniformly. Then, 5% volume-concentrated aqueous ammonia was added and the mixture was reacted at 25°C to form a polysiloxane on the surface of the alumina powder particles, thereby obtaining a precursor. Here, the mass ratio of alumina powder, MTMS, and 5% volume-concentrated aqueous ammonia was 50:1:1.

[0114] The precursors obtained in steps S2 and S1 were placed in a muffle furnace, heated to 70°C, and dried at a constant temperature for 24 hours to reduce the moisture content of the precursors to 0.6%.

[0115] In step S3, nitrogen gas was passed through the muffle furnace to create a nitrogen atmosphere inside the furnace. The temperature was then raised to 800°C at a heating rate of 5°C / min and maintained for 7 hours to perform a calcination treatment, which densified the surface of the precursor. The furnace was then cooled to room temperature to obtain a dense siloxane compound shell layer continuous with the surface of the alumina powder particles. Here, the thickness of the siloxane compound coating, i.e., the thickness of the shell layer, was 1.2 nm.

[0116] Comparative Example 1 The main difference from Example 1 was that the average particle size of the boron nitride powder in step S1 was 0.02 μm. Other aspects were the same as in Example 1.

[0117] The coating thickness of the siloxane compound obtained in this comparative example was 0.1 nm.

[0118] Comparative Example 2 The main difference from Example 1 was that the average particle size of the boron nitride powder in step S1 was 45 μm. Otherwise, it was the same as Example 1.

[0119] The coating thickness of the siloxane compound obtained in this comparative example was 103.2 nm.

[0120] Comparative Example 3 The main difference from Example 1 was that the average particle size of the boron nitride powder in step S1 was 45 μm, and the mass ratio of the boron nitride powder, MTMS, and 5% volume concentration aqueous ammonia in step S1 was 40:1:1. Otherwise, it was the same as Example 1.

[0121] The coating thickness of the siloxane compound obtained in this comparative example was 509.2 nm.

[0122] Comparative Example 4 The main difference from Example 1 was that the water content of the precursor in step S2 was 0.03%. Otherwise, it was the same as Example 1.

[0123] The coating thickness of the siloxane compound obtained in this comparative example was 1.0 nm.

[0124] Comparative Example 5 The main difference from Example 1 was that the water content of the precursor in step S2 was 1.5%. Otherwise, it was the same as Example 1.

[0125] The coating thickness of the siloxane compound obtained in this comparative example was 1.1 nm.

[0126] Comparative Example 6 The main difference from Example 1 was that the gas atmosphere used for firing in step S3 was air. Otherwise, it was the same as Example 1.

[0127] The coating thickness of the siloxane compound obtained in this comparative example was 0.9 nm.

[0128] Comparative Example 7 The main difference from Example 1 was that the firing temperature in step S3 was 600°C and the temperature was maintained for 4 hours. Otherwise, it was the same as Example 1.

[0129] The coating thickness of the siloxane compound obtained in this comparative example was 1.1 nm.

[0130] Comparative Example 8 The main difference from Example 1 was that the firing temperature in step S3 was 550°C and the temperature was maintained for 5 hours. Otherwise, it was the same as Example 1.

[0131] The coating thickness of the siloxane compound obtained in this comparative example was 1.2 nm.

[0132] Characterization of performance The filler particles having a siloxane compound shell layer, obtained by manufacturing in Examples 1-18 and Comparative Examples 1-8, were tested for particle size, Q unit content, shell layer thickness, and moisture content after standing. The analytical results are shown in Table 1. Here, the moisture content after standing was tested by leaving the open for 48 hours under environmental conditions of 25°C and 50% RH, starting from the time of manufacture. The Q unit content was measured using the manufactured solid particles. 29 In Si-NMR nuclear magnetic resonance spectroscopy, this was the ratio of the peak integral area in the -80 ppm to -120 ppm range to the peak integral area in the +20 ppm to -120 ppm range.

[0133] Table 1 JPEG2026529556000001.jpg157153

[0134] As can be seen from Table 1,

[0135] (1) As can be seen from Examples 1 to 18, the present invention uses T-unit siloxane as a raw material to form a polysiloxane layer on the surface of filler powder particles, then dries the polysiloxane layer to a low moisture content state, promotes the condensation of silyl hydroxyl groups, arranges the organic groups of T-unit siloxane in an orderly manner, forms a uniform polysiloxane layer, which helps in the formation of a dense siloxane compound, and finally sintersects some of the organic groups of T-unit siloxane to remove them and convert them to Q-units, converting the uniform polysiloxane layer into a dense siloxane compound layer. Filler particles with the resulting siloxane compound shell layer have the excellent property of having a relatively low moisture content after standing. For powders containing a siloxane compound shell layer, such as boron nitride powder, PQ60 powder, alumina powder, and aluminum nitride powder, to be applied as semiconductor fillers, the dense siloxane compound shell layer reduces water absorption during storage of the filler powder, further reduces dielectric loss during operation of electronic devices, and reduces the risk of ON due to high moisture content.

[0136] (2) Analysis of selection conditions for core filler powder particle size in the method of coating the surface of the filler powder of the present invention with a low moisture content shell layer: As can be seen from the comparative analysis of Comparative Examples 1 and 2 and Example 1, the particle sizes of the boron nitride powder in Comparative Examples 1 and 2 were 0.02 μm and 45 μm, respectively, and the moisture content was significantly increased in both cases compared to Example 1. Analysis of the cause revealed that if the particle size of the boron nitride powder is too small, it tends to aggregate easily, and the T-unit siloxane does not adhere uniformly to the surface of the boron nitride powder, making it difficult to form a uniform polysiloxane film layer and further worsening the coating effect. Since the thickness of the siloxane compound that requires coating is relatively small, the amount of raw material for the T-unit siloxane added is relatively small. Similarly, if the particle size of the boron nitride powder is too large, the siloxane does not adhere uniformly to the surface of the boron nitride powder, resulting in a non-uniform coating. This non-uniform coating leads to increased water absorption after the product is left standing. Therefore, in order to coat the surface of boron nitride powder with a shell layer with a low moisture content using the method of the present invention, it is necessary to control the particle size of the boron nitride powder within an appropriate range.

[0137] As can be seen from the comparative analysis of the characterization data of Examples 1, 6-7, and Comparative Examples 1-2, the particle size of the boron nitride powder of the present invention was preferably 0.05-40 μm. Furthermore, as can be seen from the comparative analysis of Example 8, Example 7, and Example 1, the particle size of the boron nitride powder in Example 7 was larger than that of Example 1. This can be achieved by increasing the amount of siloxane added per T unit to improve the uniformity of the coating film layer and, consequently, the density of the film layer. For example, in Example 8, the amount of siloxane added was increased, and the uniformity of the coating was superior to that of Example 7 (expressed as lower water absorption in Example 8). However, comparing Comparative Example 3 with Comparative Example 2, when the particle size of the boron nitride powder in Comparative Example 2 increased to 45 μm, the amount of siloxane added in Comparative Example 3 was also increased. In this case, the water absorption of Comparative Example 3 was greater than that of Comparative Example 2, and aggregation occurred in the boron nitride powder during the manufacturing process. As a result, it was inferred that if the amount of siloxane added per unit T was too high, the viscosity of the boron nitride powder would increase, preventing the siloxane from adsorbing uniformly onto the surface of the boron nitride powder to form a polysiloxane film layer, and ultimately reducing the density of the siloxane compound film layer obtained by calcination. Therefore, it was further inferred that in this method, the particle size of the boron nitride powder needs to be controlled within a certain range in order to form a uniform, dense siloxane compound shell layer and reduce the moisture content of the product.

[0138] (3) Analysis of the conditions for the moisture content of the precursor in the method of coating the surface of the filler powder of the present invention with a low moisture content shell layer: As can be seen from the comparative analysis of Comparative Examples 4-5 and Example 1, the moisture content of the precursors after drying in Comparative Examples 4 and 5 was 0.03% and 1.5%, respectively, and the moisture content of the products after standing increased significantly compared to Example 1. As can be seen from the above, keeping the moisture content of the precursor within a certain range helps in the formation of a dense siloxane compound, and the moisture content of the precursor was preferably low, between 0.1% and 1%. Analysis of the cause revealed that by keeping the polysiloxane layer at a low moisture content of 0.1% to 1%, the rotation of the organic groups of the T-unit siloxane can be promoted, resulting in an orderly arrangement and the formation of a uniform polysiloxane layer. Furthermore, the resulting siloxane compound shell layer is made more dense and has a relatively low porosity.

[0139] (4) Analysis of the conditions of the calcination gas atmosphere for the precursor in the method of coating the surface of the filler powder of the present invention with a low moisture content shell layer: As can be seen from the comparative analysis of Comparative Example 6 and Example 1, the gas atmosphere in the calcination process in step S3 of Comparative Example 6 was air, and the moisture content of Comparative Example 6 after standing increased significantly. Upon analysis of the cause, it was found that air contains oxygen gas, which is an active gas. The oxygen gas reacts with the carbon formed by the decomposition of organic groups, removing the carbon and then forming defects at the carbon sites. As a result, the porosity is relatively high, the shell layer is not dense, and the water absorption of the product is large. When calcination is performed in an inert atmosphere, the moisture released by the condensation of silylhydroxy groups also reacts with carbon and removes the carbon. However, because the moisture content is relatively low, the rate of carbon removal is relatively slow, and the continuous condensation of silylhydroxy groups in the film layer repairs the defect sites, resulting in a relatively low porosity.

[0140] (5) Conditional analysis of the Q content of the shell layer in a method for coating the surface of a filler powder of the present invention: As can be seen from the comparative analysis of Comparative Examples 7 and 8 and Example 1, by adjusting the temperature and time of the firing step and reducing the conversion from T units to Q units, the Q unit content of the products in Comparative Examples 7 and 8 was reduced to 48.0% and 37.2%, respectively. The moisture content of the boron nitride powder in the resulting coating shell layer after standing was reduced to 216.7 ppm / m2 and 284.5 ppm / m2, respectively, showing a significant improvement in moisture content in both cases. As can be seen from the above, in order to coat the surface of boron nitride powder with a low moisture content shell layer, it is necessary to control the Q unit content within a certain range.

[0141] (6) Selection analysis of core material in a method for coating a low-moisture-content shell layer on the surface of a filler powder according to the present invention: As can be seen from the comparative analysis of Example 1 and Examples 16-20, the selection of core material can affect the moisture content after manufacturing and storage. The core materials of Examples 1, 16, and 17 are filler materials with high surface energy, such as boron nitride, diamond, and aluminum nitride, respectively, and the moisture content of their products after storage is generally higher than that of Examples 18, 19, and 20. On the other hand, the core materials of Examples 18, 19, and 20 are organophosphorus flame retardant powder, metal magnetic powder, and alumina powder, and the surface energy of these materials is relatively lower compared to boron nitride, diamond, and aluminum nitride. As a result, it was hypothesized that core materials with high surface energy may form fine gaps between them and the shell layer after coating, resulting in relatively high porosity and further water absorption problems, and ultimately, core materials with high surface energy generally have a higher moisture content than core materials with low surface energy. Furthermore, as can be seen from the above, the final moisture content of the manufacturing process including the shell layer provided by the present invention may be related to the core material.

[0142] The organophosphorus flame retardant powder used in the embodiments of the present invention was purchased from Daiichi Kogyo Seiyaku Co., Ltd., with product model number PQ-60. The raw materials used in the embodiments of the present invention, boron nitride, alumina, and aluminum nitride, were purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.

[0143] Unless otherwise specified, the raw materials and equipment used in this invention are all commonly used in the field, and unless otherwise specified, the methods used in this invention are all commonly used in the field.

[0144] The above description is merely a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modifications, changes, and equivalent transformations made to the above embodiments based on the technical substance of the present invention all fall within the scope of the claims of the technical solutions of the present invention.

Claims

1. A shell layer with a low moisture content, Contains siloxane compounds, The siloxane compound is in the range of +20 ppm to -120 ppm. ２９ It responds in the Si-NMR nuclear magnetic resonance spectrum, solid ２９ In the Si-NMR nuclear magnetic resonance spectrum, the ratio of the peak integral area of ​​the shell layer in the -80 ppm to -120 ppm range and the +20 ppm to -120 ppm range is 50 to 99.5:

100. A shell layer characterized by a low moisture content.

2. After being left for 48 hours under environmental conditions of 25°C and 50% RH, the Karl Fischer moisture content of the product containing the shell layer at 200°C was 160 ppm / m³. ２ The following is: The low-moisture-content shell layer according to feature 1.

3. The siloxane compound is obtained by using a siloxane containing 90% wt or more of T units as a raw material. Here, T unit = R １ SiO ３ - and R1 is a hydrogen atom or a hydrocarbon group of 1 to 16 carbon atoms that can be independently selected. The low-moisture-content shell layer according to feature 1.

4. The T-unit siloxane is selected from hydrocarbon trialkoxysilanes and hydrocarbon trichlorosilanes. The low-moisture-content shell layer according to feature 3.

5. The thickness of the shell layer is 0.5 nm to 300 nm. The low-moisture-content shell layer according to feature 1.

6. Step S1: Add a T-unit siloxane to the filler powder to be coated with the shell layer, react it, and form a polysiloxane on the surface of the powder to be coated with the shell layer, thereby obtaining a precursor. Step S2: The precursor is dried to reduce its moisture content. Step S3 includes performing a calcination treatment to densify the surface of the precursor and obtain a shell layer on the surface of the filler powder, Here, T unit = R １ SiO ３ - and R1 is a hydrogen atom or a hydrocarbon group of 1 to 16 carbon atoms that can be independently selected. A method for coating a low-moisture-content shell layer according to any one of claims 1 to 5, characterized by the present invention.

7. In step S1, a basic aqueous solution is added and the reaction is carried out. The coating method according to feature 6.

8. Add more silica powder and continue the reaction. The coating method according to feature 7.

9. The particle size of the silica powder is 10 to 100 nm. The coating method according to feature 8.

10. In step S1, the particle size of the filler powder is 0.05 to 40 μm. The coating method according to feature 6.

11. In step S2, the moisture content of the precursor is reduced to 0.1-1% by drying. The coating method according to feature 6.

12. The drying process involves heating to 50-200°C and drying for 6-24 hours. The coating method according to claim 6 or 11, characterized by the features described above.

13. In step S3, the firing process is carried out in an inert gas atmosphere. The coating method according to feature 6.

14. In step S3, the firing temperature is 600 to 1200°C. The coating method according to feature 6.

15. In step S3, the firing time is 6 to 72 hours. The coating method according to feature 14.

16. A filler powder, A shell layer comprising the shell layer described in any one of claims 1 to 5, or a shell layer obtained by the coating method described in any one of claims 6 to 15. A filler powder characterized by the following features.

17. The aforementioned filler powder is one or more selected from a thermal conductive material and an organophosphorus flame retardant. The filler powder according to feature 16.

18. The aforementioned filler powder is one or more selected from boron nitride, PQ60, alumina, and aluminum nitride. The filler powder according to feature 17.

19. Application of the filler powder according to any one of claims 16 to 18 in the manufacture of semiconductor package materials or substrate materials.

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